string quartets, op. 6 no. 1 & 2 String quartets, op. 6 no. 1 & 2 string quartets nos. 1 & 2 string quartets op.76 nos. 2-4 String quartets nos. 1 & 2 string quartet no.1 & 2 string quartet op.59 no.2 string quartets nos.1 & 2 string quartets op.18, no.3&6 String quartets Nos. 1 & 2